TABLE 2.
Comparison of virulence parameters for infections with wild-type and two independently generated pbmif-ko parasitesa
| Host mice | Variable | Test statistics | Further details |
|---|---|---|---|
| BALB/c | Cumulative parasite density | F(2,12)= 8.32; P = 0.005 | Wild-type parasites (0.13 ± 0.04) did not reach significantly different densities than pbmif-ko1 parasites (0.28 ± 0.09), but pbmif-ko2 parasites (0.76 ± 0.16) reached significantly higher densities than both other genotypes. The data do not show a consistent trend for pbmif-ko parasites to reach higher densities than wild-type parasites. |
| Peak parasitemia | F(2,12) = 0.06; P = 0.946 | Wild type infections: 12.90 ± 2.32 | |
| pbmif-ko1 infections: 9.61 ± 2.14 | |||
| pbmif-ko2 infections: 11.74 ± 2.59 | |||
| Minimum mass | F(2,12) = 0.44; P = 0.653 | Wild type infections: 17.57 ± 0.38 | |
| pbmif-ko1 infections: 17.05 ± 0.44 | |||
| pbmif-ko2 infections: 16.73 ± 0.87 | |||
| Mass loss | F(2,12) = 0.11; P = 0.901 | Wild type infections: 3.33 ± 0.52 | |
| pbmif-ko1 infections: 3.08 ± 0.84 | |||
| pbmif-ko2 infections: 2.87 ± 0.67 | |||
| Minimum red blood cell density | F(2,12) = 0.18; P = 0.835 | Wild type infections: 5.07 ± 0.43 | |
| pbmif-ko1 infections: 5.04 ± 0.23 | |||
| pbmif-ko2 infections: 4.79 ± 0.39 | |||
| Red blood cell loss | F(2,12) = 0.14; P = 0.871 | Wild type infections: 5.21 ± 0.84 | |
| pbmif-ko1 infections: 4.91 ± 0.29 | |||
| pbmif-ko2 infections: 5.36 ± 0.54 | |||
| Cumulative reticulocyte density | F(2,12)= 17.69; P < 0.001 | Wild-type-infected hosts had significantly fewer reticulocytes (1.13 ± 0.07) than pbmif-ko1-infected hosts (2.51 ± 0.25) and pbmif-ko2-infected hosts (2.28 ± 0.15) | |
| Peak reticulocytemia | F(2,12)= 24.00; P < 0.001 | Wild-type-infected hosts had significantly lower peak levels of reticulocytes (2.10 ± 0.22) than pbmif-ko1-infected hosts (4.24 ± 0.35) and pbmif-ko2-infected hosts (5.56 ± 0.57) | |
| C57BL/6 | Cumulative parasite density | F(2,12) = 0.95; P = 0.415 | Wild type infections: 0.67 ± 0.15 |
| pbmif-ko1 infections: 0.50 ± 0.10 | |||
| pbmif-ko2 infections:0.79 ± 0.19 | |||
| Peak parasitemia | F(2,12) = 1.93; P = 0.188 | Wild type infections: 6.48 ± 1.54 | |
| pbmif-ko1 infections: 5.18 ± 1.27 | |||
| pbmif-ko2 infections: 10.36 ± 2.70 | |||
| Minimum mass | F(2,12) = 1.97; P = 0.182 | Wild type infections: 16.42 ± 0.42 | |
| pbmif-ko1 infections: 16.53 ± 0.46 | |||
| pbmif-ko2 infections: 16.41 ± 0.30 | |||
| Mass loss | F(2,12) = 0.03; P = 0.975 | Wild type infections: 0.34 ± 0.17 | |
| pbmif-ko1 infections: 0.82 ± 0.15 | |||
| pbmif-ko2 infections: 0.94 ± 0.32 | |||
| Minimum red blood cell density | F(2,12)= 11.84; P = 0.001 | pbmif-ko2-infected hosts were more anemic (4.74 ± 0.29) than wild-type-infected hosts (7.27 ± 0.35). pbmif-ko1-infected hosts (5.86 ± 0.43) did not have significantly different minimum red cell densities than wild-type-infected hosts. Therefore, there was not a consistent trend for pbmif-ko-infected hosts to be less anemic than wild-type-infected hosts. | |
| Red blood cell loss | F(2,12) = 2.28; P = 0.102 | Wild type infections: 2.33 ± 0.20 | |
| pbmif-ko1 infections: 2.75 ± 0.84 | |||
| pbmif-ko2 infections: 4.15 ± 0.48 | |||
| Cumulative reticulocyte density | F(2,12)= 8.61; P = 0.005 | Wild-type-infected hosts had significantly fewer reticulocytes (0.41 ± 0.10) than pbmif-ko1-infected hosts (1.57 ± 0.30) and pbmif-ko2-infected hosts (1.36 ± 0.18) | |
| Peak reticulocytemia | F(2,12)= 7.93; P = 0.006 | Wild-type-infected hosts had significantly lower peak levels of reticulocytes (2.20 ± 0.58) than pbmif-ko1-infected hosts (10.07 ± 2.35) and pbmif-ko2-infected hosts (9.23 ± 1.77) |
Results of experiment 2, in which in which BALB/c hosts and C57BL/6 hosts were infected with either wild-type parasites or one of two independent lines of pbmif-ko parasites (pbmif-ko1 and pbmif-ko2). The statistics are from general linear models, and the F ratio represents the variance attributable to each explanatory variable when the variance remaining unexplained by the model was compared. This ratio was weighted by the degrees of freedom associated with each explanatory variable and compared to the appropriate F distribution to generate the P value. For all variables, means and standard errors are shown. Variables for which wild-type infections differed significantly from pbmif-ko infections are indicated by boldface, and further explanation is provided. The units are percentages for proportion data and 109 cells/ml for density data.